I would guess you need to make a global variable IsPlayerTurn = -1. This would mean it's time for the cinematic to play.
At the start of layout if the IsPlayerTurn = - 1 then start a function where you disable the movement of the sprite, and assign your own.
After each attack set the IsPlayerTurn either to 0 or to 1. 0 for the boss's turn for example, 1 for the player's.